Dr. H. Woodward—On the Pores in Trilobites. 54] 
Tsopods (see Plate XIII. Figs. 7 & 8), or beneath, as in Limulus, 
Apus, and other forms of Entomostraca. 
Mr. John Young, F.G.8., of the Hunterian Museum, in the 
University of Glasgow, a most careful observer, and to whom I-am 
indebted for the loan of many interesting specimens of Carboniferous 
Trilobites, several of which illustrate this point in an admirable 
manner, suggests, In a note to me, that he has long thought that 
these puncta might possibly prove to be ocelli. Whether this be 
the correct interpretation or not, at any rate it seems a more 
plausible hypothesis than that suggested by Prof. M‘Coy. 
It is true that such an association of larval eye-spots with com- 
pound eyes has not as yet been met with in any of the Trinoprra, 
but it occurs in the Mrrostomata both recent and fossil (Pterygotus, 
Slimonia and Limulus), and its discovery would be hailed as further 
evidence in favour of the undoubted close affinities of both these 
groups with the Scorpionide, and so with the ARACHNIDA. 
We have noticed two instances of pores in the Isopopa, and it is 
probable that the researches into the “‘ Challenger”’ collections now 
in progress will reveal many others in this interesting group. In 
one instance, Spheroma (Pl. XIII. Fig. 7), the pore seems really to 
be on the line of the suture of the glabella, the free-cheeks in the 
Trilobite being represented in the Isopod by the first thoracic somite 
which wraps around the sides of the head in a similar manner. 
In Serolis (Pl XIII. Fig. 8) the pore, which forms rather an 
elongated slit (p), is in the centre of the margin of the first thoracic 
somite, and at a distance from the compound eye has no relation 
to any suture. These puncta may be, like the fenestrae in the head 
of Blatta orientalis, either rudimentary ocelli or the seat of some other 
nerve-sense, and may have been, as in Blatia and in Serolis, covered 
with a thin transparent portion of the integument, which served 
either as a simple eye, a tympanum, or an olfactory pore. We have 
referred to these fenestre in the head of Blatta because they are 
placed like those in the Trilobites, on a suture of the head, and in 
front of the compound eyes. 
We hope to have some further information to offer on this subject 
upon a future occasion, meantime other workers may be able to assist 
with suggestions and specimens to elucidate this interesting point, 
for which we shall be only too thankful. 
EXPLANATION OF PLATE XIII. 
Fics. 1—6. CARBONIFEROUS TRILOBITES. 
Fic. 1. Brachymetopus Ouralicus, De Vern. sp. (Outline figure restored, enlarged 
25 times natural size.) 
», 2. Brachymetopus Maccoyi, Portlock, sp. (Outline figure enlarged twice 
natural size.) 
», 3. Brachymetopus Hibernicus, H. Woodw., sp. nov. (Pygidium enlarged twice 
natural size.) 
», 4. Griffithides moriceps, H. Woodw., sp. nov. Carboniferous Limestone, 
Settle, Yorkshire. (Head only known, enlarged twice natural size.) 
[For description see Grou. Maa. p. 487. | 
5 & 6. Upper and under side of head of Phillipsia Eichwaldi, showing pore 
2? . . . . 
(p) on the upper side as an invagination of the crust, and below as a 
